JP2009533270A - Speed control device and vehicle equipped with such speed control device - Google Patents

Abstract

The present invention relates to a speed control device for a vehicle comprising a control device (12) and a user interface (26). In the control device (12), a plurality of drive modes (N, E) including different control strategies and including at least one eco mode (E) are realized. The eco-mode (E) control strategy is optimized for a fuel-saving travel mode. The user interface (26) has an input device (32) for selecting a drive mode. It is advantageously used in hybrid vehicles. The control strategy can be adjusted for different parameters of the hybrid vehicle (charge state, motor output, regenerative braking range).
[Selection] Figure 1

Description

  The present invention relates to a speed control device for a vehicle including a control device and a user interface, and a vehicle including such a speed control device.

  A known speed control device (Geschwindigkeitsregelvorrichtung) allows the speed control function to control the speed of the vehicle relative to the desired speed selected by the driver. Furthermore, an improved speed control device, ie an ACC system (Adaptive Cruise Control) is known. The ACC system further determines the position of the preceding vehicle in its own lane by means of a laser sensor or a comparable measuring system, measures the distance and relative speed of the preceding vehicle, intervenes in its own drive system and possibly brakes By intervening in the system, it is possible to control the speed so that the preceding vehicle is followed at an appropriate safety interval.

  When the deviation between the target value and the actual value (Soll / Ist-Abweichung) occurs in the framework of speed or interval control, what method and what time transition (zeitlicher Verlauf) A control strategy (Regelstrategie) is needed to decide whether the actual value is adjusted again to the target value. Examples of parameters that decisively determine this control strategy include an upper limit value and a lower limit value for acceleration of the host vehicle. The upper limit defines the maximum vehicle acceleration that should be required in the framework of the control of the vehicle drive system. Furthermore, the lower limit (negative value) defines the maximum deceleration at which the vehicle should be decelerated. Other parameters define, for example, under which conditions the intervention to the brake system takes place.

  In setting these parameters, different target settings that partially contradict each other are taken into account. On the one hand, of course, the necessary traffic safety needs to be guaranteed. Furthermore, it is necessary to realize a driving mode that is as comfortable as possible for the driver and the passengers of the vehicle and that saves fuel as much as possible. On the other hand, however, traffic flow should not be unnecessarily disturbed. Furthermore, the system operation needs to correspond to the instinct driving motion of a human driver as widely as possible. For example, if a relatively slow vehicle is followed in an overtaking lane on a highway and this vehicle subsequently exits to the right adjacent lane, the overtaking process of the own vehicle is shortened and the subsequent traffic is not obstructed. The host vehicle needs to be accelerated to the desired speed again as quickly as possible. Traditionally, the parameter settings that define the control strategy are based on a compromise between different goal settings.

  It is an object of the present invention to create a speed control device that allows a fuel saving type (kraftstoffsparend) travel mode.

  The challenge is that the control strategy is different and a plurality of drive modes including at least one eco mode are realized in the control device, and the eco mode control strategy is optimized for a fuel-saving driving mode, Furthermore, the user interface is solved according to the invention by having an input device for selecting the drive mode.

  In this method, the driver selects a particularly fuel-saving driving mode, referred to below as an eco mode (Oeko-Modus), under certain conditions, for example according to his own current priority or according to traffic conditions. Gain potential. In general, in this drive mode, the control strategy stands out at lower upper limits for acceleration and higher lower limits.

  The present invention is particularly advantageous in a vehicle having a hybrid drive (hybrid drive function, hybrid drive device, etc., Hybtridantrieb).

  In the hybrid drive system, an electric motor (Elektormortor) is provided in addition to the internal combustion engine to generate a drive output. The electric motor is powered by a rechargeable storage battery. The electric motor can be driven as a brake / generator when the vehicle is decelerated. Therefore, part of the kinetic energy can be recovered again and stored in the storage battery. Intelligent drive management helps the internal combustion engine to be driven at its optimum operating point (Betriebspunkt) as often and as long as possible. At the operating point, the internal combustion engine operates most efficiently. In this state, when the output of the internal combustion engine is not sufficient, insufficient output is provided by the electric drive (elektrischer Antrieb). On the other hand, the surplus output can be used for recharging the storage battery. With this drive concept, fuel consumption can be clearly reduced.

  According to the present invention, the driver can select the eco mode. In the eco mode, the control method is optimally adjusted to the demand for hybrid drive. For example, in this mode, an upper limit for acceleration can be established so that the required drive output can be provided by electric drive and therefore the internal combustion engine does not have to deviate from its optimum operating point. is there. Similarly, kinetic energy that is not used during deceleration can be completely converted into electrical energy by the generator, and therefore for acceleration so that no energy is lost by actuation of the vehicle friction brake. The lower limit of can be defined.

  When necessary, for example, when the traffic volume is relatively high and rather dynamic driving is appropriate, the driver is always more likely to be able to change lanes on a multi-lane roadway without risk. It is possible to switch to a “normal” drive mode in which high vehicle acceleration and deceleration are allowed.

  Preferred embodiments of the invention will be apparent from the dependent claims as defined in the appended claims.

  In the eco mode, the upper acceleration limit value (obere Beschleunigungsgrenze) is lowered in the normal mode compared to the normal mode. However, there may be situations where fuel savings are achieved by allowing higher accelerations than in normal mode. This is because, for example, in hybrid drive, the optimum acceleration for the traffic situation is so high that the necessary additional power cannot be provided by the electric drive, so that the internal combustion engine runs off its operating point. Applicable when necessary. In this case, it is advantageous to continue to increase the acceleration so that the vehicle can reach its target speed (Sollgeschwindigkeit) more quickly and the internal combustion engine can correspondingly return to the optimum operating point again early.

  When driving at a nearly constant speed, depending on the situation, it may be possible to change the target speed, especially when an inconvenient driving condition can be avoided, such as returning to a lower gear stage (Getriebestufe). May be advantageous. Conversely, in other situations, fuel savings can be achieved by slightly increasing the target speed, for example when switching to a higher gear stage is possible.

  However, there is a problem in raising the target speed beyond the desired speed selected by the driver. That is, the driver is expected to have selected this desired speed in order to comply with existing speed limits. Therefore, in the eco mode, the driver needs to obtain a warning notification when the target speed needs to be increased beyond the desired speed in order to save fuel. Or, the speed increase should only be allowed when the driver confirms the query output from the system in this connection.

  Parameters that characterize the control method, such as an upper limit value and a lower limit value for acceleration, may differ depending on the situation, for example, depending on the inclination of the roadway, the loading of the vehicle, and the like.

  In order to keep the driver's vehicle movement (Fahrzeugverhalten) in a defined state and prevent unexpected acceleration or deceleration, the effective acceleration limit value (Beschleunigungsgrenze) and target speed in the eco mode are generally The corresponding acceleration limit in normal mode and the deviation from the target speed (Abweichung) should not exceed, for example, 10%.

  In the eco mode tuned for hybrid drive, the control strategy may also depend on the state of charge of the storage battery. For example, the target speed can be reduced so that some excess output of the internal combustion engine is provided for recharging of the storage battery when the state of charge of the storage battery is low.

  In the known ACC system, an approach strategy (Eintauchstrategie, diving strategy) is mentioned as a component of the control strategy. The approach strategy determines how far the vehicle can be "closed (eintauchen)" to an appropriate safety interval when approaching a relatively slow preceding vehicle . This approach strategy can also be distinguished between the case in the eco mode and the case in the normal mode. In the framework of interval control, the target interval (Sollabstand) typically depends on speed. Furthermore, the target interval is determined by a time interval (Zeitluecke) selected by the driver within a certain limit value. The time interval indicates the time interval between the preceding vehicle and the host vehicle. In the eco mode, it is advantageous to extend this time interval to provide more room for approach strategies.

  In a vehicle equipped with a hybrid drive system, effective linkage between the speed control device and the drive management unit is aimed. When the drive manager decides on the selection of the power source (Antriebsquelle), the selection of the gear stage (Getriebestuf), etc., and it is expected that significant fuel saving will be achieved by changing the target acceleration and / or target speed In addition, this linkage can be advantageously formed so that the speed control device always gets notifications from the drive manager.

  Embodiments of the invention are illustrated in the accompanying drawings and are described in detail in the following specification.

  FIG. 1 shows an ACC system for a vehicle with a hybrid drive (Hybridantrieb) according to the invention as an example of a distance control device (Geschwindigkeitregelvorrichtung).

  The electronic control unit (elektronisches Steuergeraet) (10) includes a control unit (Regler) (12) for speed and distance control, and an drive management system (Antriebsmanagementsystem). The control device 12 for speed and interval control and the drive management system 14 communicate with each other via the bus system 16, and via the bus system 16, the interface unit 18 and the program and parameter storage device 20. Communicate with. The interface unit 18 receives measurement data for distance control from a radar sensor 22 incorporated in the vehicle, and further receives a signal from a vehicle speedometer (Geschwindigkeitsmesser) 24. The speedometer 24 indicates an actual speed (Istgeschwindigkeit) V of the host vehicle. Further, a user interface 26 is connected to the interface unit 18. The user interface 26 has a display 28 and an audio output device for outputting information to the driver in the form of a speaker 30. Furthermore, the user interface 26 includes an input device (Eingabeeinrichtung) 32 formed from one or more switching devices (Schalter). Through the input device 32, the driver can transmit a command (Bedienungsbefehl).

  The drive management system 14 controls the hybrid drive of the vehicle. The hybrid drive includes an internal combustion engine 34 and an electromechanical transducer (elektromechanischer Wandler). The electromechanical converter can be driven as an electric motor (Eletromotor) 36 and can be operated as a generator 38. In the example shown, the drive management system 14 also intervenes in the vehicle brake system 40. If the brake command is given by the control device 12 or the driver himself, the drive management system 14 can determine whether the required brake deceleration can be achieved only by the generator 38 or, in addition, the friction braking of the vehicle. A determination is made as to whether a conventional brake system 40 based on (Reibungsbremse) needs to be activated.

  The control device 12 uses the data transmitted from the radar sensor 22 and the speedometer 24 and, in some cases, with some additional information about the state of the vehicle, for example, the yaw rate (i.e., known) The method calculates a target acceleration (Sollgbeschleunigung) a. The target acceleration a is the basis for vehicle drive and / or intervention in the brake system. In the example shown here, this target acceleration is transmitted directly to the drive management system 14. The drive management system 14 determines how the required acceleration or deceleration can be achieved as fuel-efficient as possible.

  The program and parameter storage device 20 stores parameter sets and possibly program modules. The control device 12 accesses the parameter set and the program module via the bus system 16. In addition, the parameter set and program module specify two different drive modes in which the controller 12 can operate (spezifizieren). One of the drive modes is a normal drive mode N, which corresponds to a conventional function of the ACC system. The other drive mode is an eco mode (Oeko-Modus) E, which is optimized for a travel mode with as good fuel efficiency as possible according to the characteristics of hybrid drive (within certain limits). In particular, the parameter set for each drive mode stored in the program and parameter storage device 20 specifies the upper limit values a_max_N and a_max_E and the lower limit values a_min_N and a_min_E for the target acceleration a that can be output to the drive management unit 14. (An example of an acceptable range (Wertebereich)). The lower limit value is a negative value, and thus indicates the maximum vehicle deceleration allowed each time.

  As shown in FIG. 2, the upper limit value a_max_E for acceleration in the eco mode E is smaller than the corresponding upper limit value in the normal mode N. Further, the lower limit value a_min_E in the eco mode E is larger than the corresponding lower limit value in the normal mode N. Therefore, in the eco mode E, the allowable acceleration range is more strictly limited, and thus a fuel-saving travel mode can be achieved. In particular, the limit value in the eco mode can be achieved using the motor 36 or the generator 38 as much as possible for the corresponding acceleration or deceleration so that the internal combustion engine 34 does not have to deviate from its optimum operating point. Have been selected.

  However, under certain conditions, in the eco mode E, a larger upper limit value a_max_E ′ can be applied for acceleration. Rather, the upper limit value a_max_E ′ is higher than the upper limit value in the normal mode N. This may be the case, for example, if the target speed is basically greater than the current actual speed and therefore the "appropriate" acceleration of the vehicle must be very large, so that the Getriebe needs to be slow and / or Or the case where the output higher than the optimal operating point is requested | required with respect to the internal combustion engine 34 corresponds. In this case, the higher acceleration achieves the target speed more quickly, and thus the fuel-efficient state lasts only for a relatively short time, resulting in overall fuel savings.

  In FIG. 3, the system operation is illustrated by the speed-time curve (Geschwindigkeits / Zeitsdiagramm). The curve indicated by the dotted line and marked with N shows the speed transition in the normal drive mode N. On the other hand, a curve indicated by a solid line and marked with E shows a corresponding speed transition in the eco mode E.

  Between the time points t1 and t2, the acceleration in the eco mode E is smaller than the acceleration in the normal mode N. Thus, the acceleration phase correspondingly lasts relatively long. v_lim indicates a speed limit. The speed limit requests switching of the drive system to another drive state under the current drive conditions. It is expected that fuel consumption will be significantly higher when the speed is just above v_lim than when the speed is just below this limit. For this reason, in the eco mode E, it is envisaged that the target speed is lowered to a value lower than v_lim, which is different from the desired speed selected by the driver, between time points t2 and t3. Therefore, fuel saving can be utilized. This is of course also true if the desired speed selected by the driver is slightly above v_lim.

  At time t3, a slow preceding vehicle is measured by the radar sensor 22 having a measurement depth (distance) of 150 m, for example. At that time, in the eco mode E, the vehicle is immediately decelerated at a relatively small deceleration rate anyway. On the other hand, in the normal mode N, the distance to the preceding vehicle is more actively narrowed at a relatively high deceleration rate before the deceleration starts. In the example shown, a new target speed corresponding to the speed of the preceding vehicle is first achieved at time T4 in eco mode E. On the other hand, in the normal mode N, a new target speed is already achieved at an earlier time point. This means that in the eco mode rather than the normal mode N, it is allowed to slightly fall below the target distance to the preceding vehicle.

  Since the preceding vehicle has moved to the adjacent vehicle at time t5, the lane is vacant again. In the meantime, the driver has clearly increased the desired speed. In this case, the acceleration rate in the eco mode E corresponds to the further increased upper limit value a_max_E ′ in FIG. Thus, the new desired speed is already achieved at time t6. On the other hand, in the normal mode N, the acceleration stage is expected to be extended.

  The control device 12 is particularly configured to be driven in the eco mode E when the ACC system is operated. However, the driver can always switch to the normal mode N and return to the eco mode E again via the operating device (Bedienungseinrichtung) 32.

1 shows a block diagram of a speed control device according to an embodiment of the present invention. FIG. An explanatory diagram for explaining different control strategies is shown. A speed-time curve is shown to demonstrate the effect of different control strategies.

Claims (7)

In a speed control device for a vehicle, comprising a control device (12) and a user interface (26),
A plurality of drive modes (N, E) including different control strategies and including at least one eco mode (E) are realized in the control device (12),
The eco-mode (E) control strategy is optimized for fuel-saving driving modes,
The speed control device for a vehicle, wherein the user interface (26) has an input device (32) for selecting a driving mode. The control device (12) is provided for calculating the target acceleration (a) of the vehicle within the allowable target acceleration range.
The speed control apparatus according to claim 1, wherein the range is different for different drive modes.   The limit values (A_max_E, A_max_E, a_min_E ′) of the range in the eco mode (E) differ by up to 10% from the corresponding limit values (a_max_N, a_min_N) of the range in one or more other drive modes. The speed control apparatus according to claim 2, wherein:   For vehicles with a hybrid drive, the control strategy in the eco mode (E) depends on the driving conditions and / or performance of the different drive and brake components (34, 36, 38) in the hybrid drive. The speed control device according to any one of claims 1 to 3, wherein   In the eco mode (E), the control device (12) is provided for controlling according to a driving state of the hybrid drive to a target speed different from a desired speed selected by a driver. The speed control device according to claim 4.   The speed control device according to claim 5, wherein the target speed is different from the target speed in one or a plurality of other driving modes (N) by 10% at the maximum in the eco mode (E).   A vehicle equipped with a hybrid drive, characterized by the speed control device according to any one of claims 1 to 6.

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